Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

287
FXUS63 KLOT 040726
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
226 AM CDT Sat Apr 4 2026

.KEY MESSAGES...

- Showers and storms along a passing cold front are expected
  through the morning, exiting to the east by the afternoon

- Colder and drier conditions are expected through the early
  part of next week.

- Temperatures warm up again toward the tail end of next week,
  but it comes with another chance of precipitation.

&&

.DISCUSSION...
Issued at 226 AM CDT Sat Apr 4 2026

Recent SPC mesoanalysis depicts an area of surface low pressure
in northeastern Iowa at the time this discussion was published.
That low is projected to continue a east-northeast track toward
the northern Great Lakes and Ontario thereafter. Yesterday`s
warm front appears to have stalled south of the forecast area,
prompting nudging minimum temperatures downwards for this
morning for the cooler air mass that remains north of it. No
matter, a surface cold front in connection with the previously
mentioned low will sweep across the region this morning. The
showers and thunderstorms that are presently along and ahead of
it crossing the Mississippi will continue to move eastward
through the morning. The severe threat with these storms appears
fairly low. There is technically a risk for localized gusty
winds with them, but the better well of DCAPE looks closer to
the warm front, south of the forecast area. The bigger concern
would be from localized downpours over already saturated soils.
Recent MRMS data has inch per hour rain along the front, with
localized spots up to 2 inches per hour. While the front is
progressive, it is only moving at around 25 to 30 mph. An Areal
Flood Warning was issued for the areas that received the most
precipitation last night, but a Flood Watch remains in place for
the rest of the forecast area through 10 AM this morning.

The front should be over northwest Indiana by mid-morning and
continuing to move east away from the area through the
afternoon. A stray lingering shower may be possible in the
afternoon as it pulls away, but drier conditions are expected
later today. Winds will turn to the west behind the front, and
will become breezy. As a low level jet strengthens tonight,
model soundings continue to show mixing into the 40 knot winds
at the top of the channel, which can result in gusts over 30 mph
through the overnight tonight. Lastly, high res guidance is
picking up on a mid level short wave wrapping around a larger
upper level trough tonight over Wisconsin. Guidance has shown
little agreement on whether or not any sprinkles or a brief
light rain would develop. It appears that the better forcing
would be farther north in Wisconsin, and with a lack of deep
moisture in soundings, confidence is low in precipitation. It
was decided to throw some "silent PoPs" (between 10 to 15
percent chance) for the northern tier of counties along the
Wisconsin border.

Another short wave trough is expected to drop southward out of
Canada on Sunday, sending yet another cold front across the
area that night. Models are suggesting that this front will be
a little more moisture starved than today`s front, but still
enough for recent models to suggest a slight chance (20 percent
or less) for a passing shower - though most of the area will
remain dry. More impressively with this front will be it
ushering in a much colder air mass in its wake. 850 mb
temperatures drop down below freezing on Monday morning, and
down near -10C by Tuesday morning. Our recent stretch of
temperatures in the 50s and 60s (or higher) probably makes us
forget that having low temperatures in the 30s is quite
seasonable. But the reminder will arrive Monday morning, with
low temperatures in the 20s expected on Tuesday morning.
Luckily, considering how April weather can change fairly
quickly, it will not be a permanent cold snap.

An upper level ridge is expected to develop in the middle up
next week. As the ridge grows, afternoon high temperatures will
warm up once again into the 50s and 60s, maybe even low 70s by
the end of next week. Long range guidance is projecting another
upper level trough to move over the northern Plains and Great
Lakes from Wednesday night into the end of next week and
potentially another one entering next weekend. There will likely
be breaks in the rain, but after a quieter stretch of
precipitation, it looks like a wetter pattern may return by the
end of next week.

DK

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 1257 AM CDT Sat Apr 4 2026

Aviation forecast concerns for the 06Z TAFs:

- Periods of RA/TSRA this morning ahead of a cold front. Brief
  IFR vis possible in heavier SHRA/TSRA.

- IFR/LIFR ceilings possible at times until mid-morning, then
  mainly MVFR there after.

- Blustery west winds develop behind the cold front by mid-late
  morning, with gusts 25-30 kts through the afternoon and into
  tonight. Low-probability potential for a period of 30-35 kt
  gusts this evening.

Surface low pressure was analyzed over northeast IA as of
midnight, with a warm front extending east-southeast across
central IL/IN and a cold front trailing from southeast IA
southwest across MO. This low will track east-northeast along
the IL/WI border region through daybreak, with periods of
scattered showers and thunderstorms expected prior to the cold
frontal passage this morning. IFR/occasionally LIFR ceilings
are likely, with visibilities in IFR/low-MVFR range at times in
heavier showers/storms. A few scattered showers may linger
immediately behind the cold front mid-late morning, though
visibilities should improve to P6SM. MVFR ceilings are expected
to linger for some time behind the front, gradually rising later
in the afternoon/evening and could become at least briefly VFR
later this afternoon.

Current east-northeast surface winds are expected to turn more
southeasterly predawn as the low approaches, eventually turning
abruptly southwest to west with the passage of the cold front
around 11Z at RFD and 12-13Z across the Chicago terminals. Winds
will become fairly blustery from the west by mid-late morning,
with gusts 25-30 kts expected. These blustery winds are expected
to persist into tonight, and some guidance depicts the
potential for gusts in the 30-35 kt range at times this evening,
though confidence is fairly low with this given poor diurnal
timing.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch until 10 AM CDT this morning for ILZ003-ILZ004-
     ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-ILZ019-
     ILZ020-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039-ILZ103-ILZ104-
     ILZ105-ILZ106-ILZ107-ILZ108.

IN...Flood Watch until 10 AM CDT /11 AM EDT/ this morning for
     INZ001-INZ002-INZ010-INZ011-INZ019.

LM...Small Craft Advisory from 10 AM this morning to 10 AM CDT
     Sunday for the IL and IN nearshore waters.

&&

$$

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